The layout features a stepper design implemented in MD to sequentially control the Master Generals registrations. Other functions control organ and Hauptwerk functions. The capability of Midi Designer for organ midi control is very flexible.
The layout controls corresponding organ Stops, Couplers, Pistons, and Cued Combo selection. The layout is based on the St. Anne’s Mosely organ, but the concept will work for other Hauptwerk organ sets as well.
The Stops are in the original organ layout. The Cued Combo and Master Generals are layed out to duplicate the functionality of the organ. The Cued Combo DOWN and UP buttons trigger the appropriate sequential change represented by the left and right arrows in the picture.

The Sync indicates the organ setting may be out of sync with the MD Display.
The 20 Master Generals trigger the corresponding Master General piston in the organ. Additionally, the DOWN and UP buttons in MD execute a stepper function for the Master Generals (which is not a built-in function of the organ). “C” will clear pistons and Master Generals in both the organ and MD. It does not affect the Cued Combo setting.
The display may be split between 2 iPads, resulting in larger, easier to touch buttons.
All buttons in MD need to be auto-detected in HW and appropriate registrations set up as described in the HW manual.
Design modifications can include adding a “SET” button, adding other buttons such as “CR to SW”, adding the 100 step “Stepper” function (xx0 to 999), and layout changes to suit the organist.